| dc.description.abstract | Due to the impact of global climate change and fragile geological background, the slope-land disasters such as landslides and debris flows caused by highly intense rainstorms occur more frequently in Taiwan. Alluvial fans at foothills in Taiwan often accommodate villages and infrastructures, and are high-risk areas prone to the landslides and debris flows. In this study, the formation and the process of alluvial fans is explored by using experimental study with a small-scale flume basin model equipping with silo, laser lights and cameras. By changing the sediment concentration (i.e., the ratio of sediment discharge(Qs) to water discharge (QW)) and the base-level water depths, the longitudinal profiles, cross profiles, fan shapes, angles of topset and foreset angle have been analyzed. The size of the silo opening and particle size control the particle discharge. The longitudinal profiles of the fans depict a concave shape, while the lateral profiles are convex. The angles of topset slope decrease with decreasing sediment concentration, while the foreset slopes with tail water are close to the friction angle of the sediment. Overall, the effect of channel slope on the formation of fan is less than sediment concentration and the base level. | en_US |